1. Technical Field
The present disclosure generally relates to safety devices for electrical circuit breakers and, more particularly, to a system and device for preventing the inadvertent engagement of a push-pull circuit-breaker.
2. Background of the Invention
The U.S. Occupational Safety and Health Administrations' (“OSHA”) Control of Hazardous Energy (Lock-Out/Tag-Out) (“LOTO”) standards, Title 29 Code of Federal Regulations (CFR) Parts 1910.147, 1019.333, require employees that perform work inside of an electrical panel to de-energize live parts of a circuit to which an employee may be exposed before the employee works on or near them. This standard applies to employees that service machines and equipment in which an unexpected energization or start-up of the machines or equipment, or release of stored energy, could harm the employee.
Under the standard, a person servicing, for example, electrically-powered machines or equipment is required to disengage a circuit breaker coupled to the component and apply a locking or “lock-out” device to the breaker to prevent the circuit breaker from inadvertently engaging while the component is being serviced. In addition to being de-energized and locked-out, such equipment or and circuits must be tagged at all points of work where the equipment or circuits can be energized. Such tags must be attached to the inoperative equipment and circuits such that the tags may be seen in plain sight. The tags must also identify the equipment or circuits currently being serviced. Further, in order to comply with LOTO standards, the lock-out device must not be capable of being removed from the circuit breaker by hand—the lock-out device must be removed by some sort of equipment or tool.
In applying the LOTO standards to, for example, circuit panels 100 in aircraft structures, push-pull actuated circuit breakers 102 commonly used in these types of applications must be disengaged from the circuit panel 100 before a technician may service equipment or circuits coupled to the breaker 102. Once the circuit breaker 102 is disengaged, a lock-out device 104 must be secured to the circuit breaker knob to prevent the circuit breaker from being depressed. One example of a commonly used lock-out device is the multipart Skykit® system (which includes the Skylox®, Skyvault®, Skytag®, and Skyclip®), sold by Kascar, LLC, One Kascar Plaza, Greenville, S.C. 29605. Such lock-out devices, while effective, carry a host of undesirable characteristics.
First, as best shown in FIG. 1a, existing lock-out devices 104 are bulky and often protrude out from the circuit panel 100. In some instances, the lock-out devices 104 may protrude from the circuit panel 100 more than an inch or so. This protrusion reduces the useable workspace of a technician because, as shown in FIG. 1b, the passageways in electrical bays (“E-bay”) of aircraft structures are very tight and, as such, technicians 106 frequently snag or bump into the lock-out device 104 while passing through the E-bay. Because circuit breaker knobs are not intended to be loaded, only to be pushed in or pulled out, the breaker knobs 102 upon which the lock-out devices 104 are applied may be sheared or snapped-off when the lock-out devices 104 are inadvertently engaged by a technician 106 passing through the E-bay.
The replacement of one damaged circuit breaker may cost several thousand dollars. Thus, the replacement of several damaged breakers during the service or maintenance of an aircraft structure can be very costly.
A second characteristic of existing lock-out devices is that they generally comprise several parts. For example, the commonly used Skykit® system comprises six separate parts: the Skylox® (which comprises two half-shells and an O-ring), the Skyvault®, the Skytag®, and the Skyclip®. In the aviation industry, in particular, objects laying around an aircraft that are not part of the operation are referred to as FOD. FOD, which stand for foreign object debris, refers to any substance, debris or article alien to a vehicle or system which would potentially cause damage. FOD often migrate around aircraft structures and the use of existing multi-part lock-out devices increases FOD risk. As such, there is a need for a low profile lock-out system comprising a minimal number of parts.